The Zircaloy-a clad, swaged UOa, 19-rod cluster fuel element for the PRTR was designed to use Zircaloy-a wire spirally wrapped around the fuel rods as spacing members. Such use of unbonded, Zircaloy-a spacers introduced the possibility of fretting corrosion. This paper reports preliminary irradiation tests conducted to determine whether or not such corrosions occurs in this fuel element design.

The basic process for fabricating a swaged fuel rod is simple, easy to control and inexpensive. A zircaloy tube is filled with uranium dioxide powder, the ends temporarily plugged and the loaded tube is swaged to compact the UO2 powder to the required density. The swaged rod is then cut to length and counterbored and then end cape are welded into each end. After several tests and inspections, nineteen rods which meet the quality standards are assembled into a single fuel element ready for irradiation.

A series of diffusion length measurements were carried out on graphite stacks of various constructions in an attempt to resolve the discrepancies between the graphite diffusion lengths measured in the Hanford reactors and that value measured in the Hanford Standard Pile. It was found that the diffusion length of the graphite in the Hanford reactors is in good agreement with the value for the Hanford Standard Pile when corrections are made for the absorption and scattering of neutrons by the aluminum process tubes, and for neutrons streaming in the channels of the reactors.

Plankton collected from the Columbia River by the net method and by the centrifuge method were compared. The centrifuged plankton (nannoplankton) exceeded the net plankton in weight, in abundance of organisms and in radioactivity. Similar seasonal trends were present in both types of plankton.